It is known for movable or pivotally supported structural parts in automotive vehicles, such as, for example, glove compartment covers, lids for ash-trays, holding grips or the like to exert a bias thereon by means of a spring and/or gravity. In connection with a cover for a glove compartment such a part is biased by a spring towards the open position. When actuated in the closed position it is only necessary to release the locking mechanism so that the cover opens automatically. In the case of a holding grip such a part is automatically biased towards its rest position. It is also known to dampen the movement of such structural parts by suitable damping means in order to moderate the effect of the spring means. Thus, undesired acoustic effects and wear are avoided. In many cases so-called rotary dampers are used. Rotary dampers usually include a rotor rotatably supported in a housing. A pinion is mounted upon the shaft of the rotor which meshes with a tooth segment. If a flap, cover or lid or the like is moved, the rotor is contemporarily rotated. A gap is formed between the rotor and the housing filled with a viscous medium adapted to perform a rotary dampening operation. A typical rotary damper is disclosed in the German patent publication DE 33 20 069.
Conventional rotary dampers have a damping effect in both rotational directions. In many cases this is not desired. If for example a cover for a glove compartment is biased to its opened position by a spring or by gravity, this force has to be overcome if the cover is closed manually. Also the damping effect of the rotary damper has to be overcome which may require a relatively high force.
Therefore, it has also become known to provide the rotary dampers with a free wheel mechanism. Such rotary dampers have a damping effect only in one rotational direction, whereas in the opposite direction the resistance against rotation is relatively small. Such a rotary damper is known from the German patent publication DE 37 22 114. Between the rotor and a shaft a ratchet clutch is connected such that a locking takes place only in one rotational direction. The coupling parts are biased by a spring towards each other. From the Austrian patent publication OE 224 496 it is known to provide a rotary damper for the hinge of a door, with the damper including a clutch spring which coacts with the walls of bores of the parts to be coupled. A disengagement of the coupling parts is achieved when the spring is wound up.
Rotary dampers which include a pinion and a tooth segment may develop noise. Above all, if the space between the pinion and segment changes, noise may not be avoided. Conventional arrangements of the kind described, however, cannot avoid tolerances.